Reliability Analysis And Evaluation Of Adhesive Fatigue Of Offshore Wind Turbine Blades Under Multi-environmental Stres

With onshore wind power becoming increasingly saturated,offshore wind power is growing rapidly.As one of the main load-bearing components of offshore wind turbines,the performance and reliability of offshore wind turbine blades(OWTBs)is crucial to ensure the safe operation of the entire system.However,under the action of environmental stresses such as marine thermal gradients,high humidity and strong salt spray,the fatigue resistance of the bonded structure of OWTBs is severely degraded,and fatigue failure problems such as interface failure,bond cracking and bond aging are easily induced,seriously threatening the service safety and reliability of OWTBs.Therefore,analyzing and evaluating the fatigue performance of OWTBs bonded under the influence of multiple environmental stresses is particularly important to improve blade fatigue life,and ensure safe and efficient blade operation.Based on the background of the actual service environment of the offshore wind turbine,the composite laminate bonding structure of the OWTBs is taken as the research object in this paper.And based on the progressive research idea of "Multi-environment accelerated aging test"-"Fatigue degradation simulation"-"Fatigue reliability modeling and analysis" of OWTBs bonding structure,the research on the bonding fatigue reliability of OWTBs under the influence of multi-environment stress is carried out,which provides theoretical basis for the prediction of blade service life and structural optimization design.The main research contents of the paper include the following aspects:(1)Study on the fatigue characteristics and failure mechanism of bonded structures of OWTBs under the influence of multiple environmental stresses.By conducting accelerated aging tests and fatigue tests on OWTBs bonded specimens under the influence of multiple environmental stresses,and using fatigue life as the bonding performance parameter index,the degradation of bonding performance under the single environmental stress and multiple environmental stress coupling was studied by using the orthogonal test method,and the influence mechanism of different environmental stress levels on the bonding samples were revealed.(2)Fatigue simulation study of blade bonding based on multi-environmental degradation factor model.Aiming at the problems of a long cycle,high cost and small sample data of the environmental aging test,a combined experimental-numerical simulation method for fatigue performance analysis based on a multi-environmental degradation factor model is proposed for fatigue performance analysis.Based on multi-environmental aging accelerated fatigue test data,a multi-environmental degradation factor model was established and introduced into the Cyclic Cohesive Zone Model(CCZM),and the bond fatigue damage behavior simulation analysis and fatigue performance degradation patterns under the influence of multiple environmental stresses is presented in this paper.(3)Study on the reliability analysis and evaluation of OWTBs bonding.Based on the multi-environmental degradation factor model and CCZM,the analysis of bonding fatigue performance degradation of OWTBs is completed.Considering factors such as multi-phase bonding performance and variable points,the multi-phase Wiener stochastic process is used to describe bonding fatigue performance degradation,and the bonding fatigue reliability model of OWTBs under the influence of multiple environments is established.Finally,the analysis and evaluation of bond fatigue reliability of OWTBs were completed.